The present invention relates to molded thermoplastic resin cases for transport and handling of beverage bottles, particularly those suited to receive bottles which are in a carrier.
Plastic cases for beverage bottles are generally rectangular and have a floor which is a latticework of floor support ribs. The floor is made this way to minimize the weight of the case, to minimize any accumulation of debris in the case, and to make it easier to wash out. The inner space in the case is somehow divided into bottle receiving compartments suited to the bottle size to be accepted by it.
In one type of case the inner space is divided into compartments by a number of pillars which extend vertically from the floor. The pillars have a roughly cross-shaped cross-section and are placed so that they extend vertically in the space between a group of four bottles to keep the bottles spaced sufficiently that they do not break when they are jostled. In some cases of this type, the pillars are slotted in at least one direction, parallel to the side walls or to the end walls, to form a group of two or four facing pillars. This permits bottles to be accepted together with a hand carrier, such as a "six-pack" carrier of cardboard. Such a case is described, for example, in the U.S. Pat. No. 4,071,162, which is assigned to the same assignee as that of the rights to the present invention. One or more walls of the carrier are slid into the aligned slots of the pillars. The pillars enter the carrier through openings in the bottom of the carrier. The pillars thereby supplement the protection against breakage which is afforded by the carrier alone. When the bottles are returned empty without the carrier, they can be returned alone to the case and are then similarly protected by the pillars. This protection is very important, since inadequately protected empty bottles can easily develop hairline fractures which render them unsuitable for refilling, but which are very difficult to reliably detect.
A persistent problem with cases of the type described above having slotted pillar groups has been that with certain configurations of the floor lattice, particularly a cartesian or rectangular configuration, the pillars of a group move together after the molding of the case, thereby impairing the loading of a carrier into the case due to insufficient slot clearance for readily accepting the carrier wall in the slot. This reduced slot clearance is a result of warping which occurs upon cooling of the case after demolding. Yet, for material economy and other structural reasons it is often preferred to use a cartesian floor lattice pattern.